This invention relates to a method of removing oxygen from hydrogen, hydrocarbon gases, and halogenated hydrocarbon gases that contain about 0.01 to about 10 mole % oxygen. In particular, it relates to the use of a Hopcalite catalyst at a temperature of about 100.degree. to about 300.degree. C. to remove oxygen from these gases.
A new process for producing 1,2-dichloroethane (EDC) in two steps is disclosed in WO 92/10447, herein incorporated by reference. In that process, ethane and chlorine are first reacted (in a two step reaction) to form ethylene and hydrogen chloride. That reaction occurs at high temperatures and the presence of oxygen in the reaction can burn the hydrocarbons and result in an explosion hazard. Also, the burning of the hydrocarbons with oxygen results in the formation of water which, in the presence of the hydrogen chloride, produces corrosive hydrochloric acid. Thus, it is necessary to exclude oxygen during that reaction.
The product of the reaction, ethylene and hydrogen chloride, is reacted with oxygen in an oxychlorinator at a lower temperature to form EDC. Excess oxygen is used in the oxychlorinator and the EDC product contains not only excess oxygen but also unreacted ethane from the first reaction. Once the EDC has been removed, the remaining mixture, which is mostly ethane, could be recycled to the first reaction, provided that the oxygen can be removed from it first. (Until the discovery of this new process, oxygen removal was not necessary because conventional processes for producing EDC began with ethylene, not ethane.)
Hopcalite catalysts, a mixture of copper and manganese oxides, are widely used to remove pollutants from air by catalyzing the reaction of the pollutants with oxygen. For example, Hopcalite catalysts have been used to catalyze the reaction of carbon monoxide, nitrogen oxides, ozone, and chlorinated hydrocarbons. In these reactions, the pollutant is present at a very low concentration in a huge excess of oxygen. The catalyst is thereby maintained in a higher oxidation state (CuO and MnO.sub.2) by reaction with oxygen and immediately returns to the higher oxidation state after being reduced by reaction with a pollutant.